1
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Ma HN, Hsiang CC, Ng IS. Tailored expression of ICCM cutinase in engineered Escherichia coli for efficient polyethylene terephthalate hydrolysis. Enzyme Microb Technol 2024; 179:110476. [PMID: 38944965 DOI: 10.1016/j.enzmictec.2024.110476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 06/23/2024] [Accepted: 06/25/2024] [Indexed: 07/02/2024]
Abstract
Enzymatic depolymerization of PET waste emerges as a crucial and sustainable solution for combating environmental pollution. Over the past decade, PET hydrolytic enzymes, such as PETase from Ideonella sakaiensis (IsPETases), leaf compost cutinases (LCC), and lipases, have been subjected to rational mutation to enhance their enzymatic properties. ICCM, one of the best LCC mutants, was selected for overexpression in Escherichia coli BL21(DE3) for in vitro PET degradation. However, overexpressing ICCM presents challenges due to its low productivity. A new stress-inducible T7RNA polymerase-regulating E. coli strain, ASIAhsp, which significantly enhances ICCM production by 72.8 % and achieves higher enzyme solubility than other strains. The optimal cultural condition at 30 °C with high agitation, corresponding to high dissolved oxygen levels, has brought the maximum productivity of ICCM and high PET-hydrolytic activity. The most effective PET biodegradation using crude or pure ICCM occurred at pH 10 and 60 °C. Moreover, ICCM exhibited remarkable thermostability, retaining 60 % activity after a 5-day reaction at 60 °C. Notably, crude ICCM eliminates the need for purification and efficiently degrades PET films.
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Affiliation(s)
- Hsing-Ning Ma
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Chuan-Chieh Hsiang
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
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2
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Udaypal, Goswami RK, Mehariya S, Verma P. Advances in microalgae-based carbon sequestration: Current status and future perspectives. ENVIRONMENTAL RESEARCH 2024; 249:118397. [PMID: 38309563 DOI: 10.1016/j.envres.2024.118397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/02/2024] [Accepted: 01/30/2024] [Indexed: 02/05/2024]
Abstract
The advancement in carbon dioxide (CO2) sequestration technology has received significant attention due to the adverse effects of CO2 on climate. The mitigation of the adverse effects of CO2 can be accomplished through its conversion into useful products or renewable fuels. In this regard, microalgae is a promising candidate due to its high photosynthesis efficiency, sustainability, and eco-friendly nature. Microalgae utilizes CO2 in the process of photosynthesis and generates biomass that can be utilized to produce various valuable products such as supplements, chemicals, cosmetics, biofuels, and other value-added products. However, at present microalgae cultivation is still restricted to producing value-added products due to high cultivation costs and lower CO2 sequestration efficiency of algal strains. Therefore, it is very crucial to develop novel techniques that can be cost-effective and enhance microalgal carbon sequestration efficiency. The main aim of the present manuscript is to explain how to optimize microalgal CO2 sequestration, integrate valuable product generation, and explore novel techniques like genetic manipulations, phytohormones, quantum dots, and AI tools to enhance the efficiency of CO2 sequestration. Additionally, this review provides an overview of the mass flow of different microalgae and their biorefinery, life cycle assessment (LCA) for achieving net-zero CO2 emissions, and the advantages, challenges, and future perspectives of current technologies. All of the reviewed approaches efficiently enhance microalgal CO2 sequestration and integrate value-added compound production, creating a green and economically profitable process.
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Affiliation(s)
- Udaypal
- Bioprocess and Bioenergy Laboratory (BPBEL), Department of Microbiology, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Rahul Kumar Goswami
- Bioprocess and Bioenergy Laboratory (BPBEL), Department of Microbiology, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Sanjeet Mehariya
- Algal Technology Program, Center for Sustainable Development, College of Arts and Sciences, Qatar University, Doha, 2713, Qatar
| | - Pradeep Verma
- Bioprocess and Bioenergy Laboratory (BPBEL), Department of Microbiology, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India.
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3
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Wen K, Tao Y, Jiang W, Jiang L, Zhu J, Li Q. (De)carboxylation mechanisms of heteroaromatic substrates catalyzed by prenylated FMN-dependent UbiD decarboxylases: An in-silico study. Int J Biol Macromol 2024; 260:129294. [PMID: 38211929 DOI: 10.1016/j.ijbiomac.2024.129294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/24/2023] [Accepted: 01/05/2024] [Indexed: 01/13/2024]
Abstract
The UbiD enzymes are proposed to catalyze reversible (de)carboxylation reaction of unsaturated carboxylic acids using prenylated flavin mononucleotide (prFMN) as a cofactor. This positions UbiD enzymes as promising candidates for converting CO2 into valuable chemicals. However, their industrial-scale biotransformation is currently constrained by low conversion rates attributed to thermodynamic limitations. To enhance the carboxylation activity of UbiD enzymes, a molecular-level understanding of the (de)carboxylation mechanisms is necessary. In this study, we investigated the reaction mechanisms of heteroaromatic substrates catalyzed by PtHmfF, PaHudA, and AnlnD enzymes using molecular dynamics (MD) simulations and free energy calculations. Our extensive mechanistic study elucidates the mechanisms involved in the formation of the initial prFMN-substrate intermediate. Specifically, we observed nucleophilic attack during decarboxylation, while carboxylation reactions involving furoic acid, pyrrole, and indole tend to favor a 1,3-dipolar cycloaddition mechanism. Furthermore, we identified proton transfer as the rate-limiting step in the carboxylation reaction. In addition, we considered the perspectives of reaction energies and electron transfer to understand the distinct mechanisms underlying decarboxylation and carboxylation. Our calculated free energies are consistent with available experimental kinetics data. Finally, we explored how different rotamers of catalytic residues influence the efficiency of the initial intermediate formation.
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Affiliation(s)
- Kai Wen
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Yu Tao
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Wenyan Jiang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Liyan Jiang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Jingxuan Zhu
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China.
| | - Quanshun Li
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China; Center for Supramolecular Chemical Biology, Jilin University, Changchun 130012, China.
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Chen JP, Gong JS, Su C, Li H, Xu ZH, Shi JS. Improving the soluble expression of difficult-to-express proteins in prokaryotic expression system via protein engineering and synthetic biology strategies. Metab Eng 2023; 78:99-114. [PMID: 37244368 DOI: 10.1016/j.ymben.2023.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 05/23/2023] [Indexed: 05/29/2023]
Abstract
Solubility and folding stability are key concerns for difficult-to-express proteins (DEPs) restricted by amino acid sequences and superarchitecture, resolved by the precise distribution of amino acids and molecular interactions as well as the assistance of the expression system. Therefore, an increasing number of tools are available to achieve efficient expression of DEPs, including directed evolution, solubilization partners, chaperones, and affluent expression hosts, among others. Furthermore, genome editing tools, such as transposons and CRISPR Cas9/dCas9, have been developed and expanded to construct engineered expression hosts capable of efficient expression ability of soluble proteins. Accounting for the accumulated knowledge of the pivotal factors in the solubility and folding stability of proteins, this review focuses on advanced technologies and tools of protein engineering, protein quality control systems, and the redesign of expression platforms in prokaryotic expression systems, as well as advances of the cell-free expression technologies for membrane proteins production.
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Affiliation(s)
- Jin-Ping Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, PR China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing, 214200, PR China
| | - Jin-Song Gong
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, PR China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing, 214200, PR China.
| | - Chang Su
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, PR China
| | - Heng Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, PR China
| | - Zheng-Hong Xu
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, School of Biotechnology, Jiangnan University, Wuxi, 214122, PR China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, PR China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing, 214200, PR China
| | - Jin-Song Shi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, PR China; Yixing Institute of Food and Biotechnology Co., Ltd, Yixing, 214200, PR China
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Lin JY, Ng IS. Enhanced carbon capture, lipid and lutein production in Chlamydomonas reinhardtii under meso-thermophilic conditions using chaperone and CRISPRi system. BIORESOURCE TECHNOLOGY 2023:129340. [PMID: 37343802 DOI: 10.1016/j.biortech.2023.129340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/23/2023]
Abstract
Microalgae are widely recognized as a promising bioresource for producing renewable fuels and chemicals. Microalgal biorefinery has tremendous potential for incorporation into circular bioeconomy, including sustainability, cascading use, and waste reduction. In this study, genetic engineering was used to enhance the growth, lipid and lutein productivity of Chlamydomonas reinhardtii including strains of CC400, PY9, pCHS, and PG. Notably, CRISPRi mediated on phosphoenolpyruvate carboxylase (PEPC1) gene to down-regulate the branch pathway from glycolysis to partitioning more carbon flux to lipid was explored under meso-thermophilic condition. The best chassis PGi, which has overexpressed chaperone GroELS and applied CRISPRi resulting in the highest biomass of 2.56 g/L and also boosted the lipids and lutein with 893 and 23.5 mg/L, respectively at 35 °C. Finally, all strains with CRISPRi exhibited higher transcriptional levels of the crucial genes from photosynthesis, starch, lipid and lutein metabolism, thus reaching a CO2 assimilation of 1.087 g-CO2/g-DCW in mixotrophic condition.
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Affiliation(s)
- Jia-Yi Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
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Diankristanti PA, Effendi SSW, Hsiang CC, Ng IS. High-level itaconic acid (IA) production using engineered Escherichia coli Lemo21(DE3) toward sustainable biorefinery. Enzyme Microb Technol 2023; 167:110231. [PMID: 37003250 DOI: 10.1016/j.enzmictec.2023.110231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/17/2023] [Accepted: 03/19/2023] [Indexed: 03/31/2023]
Abstract
Itaconic acid (IA) serves as a prominent building block for polyamides as sustainable material. In vivo IA production is facing the competing side reactions, byproducts accumulation, and long cultivation time. Therefore, the utilization of whole-cell biocatalysts to carry out production from citrate is an alternative approach to sidestep the current limitations. In this study, in vitro reaction of IA was obtained 72.44 g/L by using engineered E. coli Lemo21(DE3) harboring the aconitase (Acn, EC 4.2.1.3) and cis-aconitate decarboxylase (CadA, EC 4.1.1.6) which was cultured in glycerol-based minimal medium. IA productivity enhancement was observed after cold-treating the biocatalysts in - 80 °C for 24 h prior to the reaction, reaching 81.6 g/L. On the other hand, a new seeding strategy in Terrific Broth (TB) as a nutritionally rich medium was employed to maintain the biocatalysts stability up to 30 days. Finally, the highest IA titer of 98.17 g/L was attained using L21::7G chassis, that has a pLemo plasmid and integration of GroELS to the chromosome. The high-level of IA production along with the biocatalyst reutilization enables the economic viability toward a sustainable biorefinery.
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Li S, Wang Y, Jiang H, Bai Y, Chen T, Chen M, Ma M, Yang S, Wu Y, Shi C, Wang F, Chen Y. Display of CCL21 on cancer cell membrane through genetic modification using a pH low insertion peptide. Int J Biol Macromol 2023; 240:124324. [PMID: 37023874 DOI: 10.1016/j.ijbiomac.2023.124324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/08/2023]
Abstract
CCL21, a secondary lymphoid tissue chemokine, plays an important role in generating an effective anti-tumor immune response. In this study, a genetically modified CCL21 was developed by inserting a pH low insertion peptide to establish a CCL21-rich microenvironment for tumors. The fusion tag thioredoxin (Trx) was designed and fused at the N-terminal of the recombinant protein to protect it from being irrevocably misfolded in microbial host cells. The prokaryotic expression vector pET32a-CCL21-pHLIP was constructed and successfully expressed in E. coli BL21 (DE3) with a soluble expression form and a molecular weight of ~35 kDa. The induction conditions were optimized to obtain an extremely high yield of 6.7 mg target protein from 31.1 mg total protein. The 6xHis tagged Trx-CCL21-pHLIP was purified using Ni-NTA resin, and it was confirmed using SDS-PAGE and Western blot analyses. Consequently, the Trx-CCL21-pHLIP protein was successfully displayed on the cancer cell surface in a weak acidic microenvironment and showed the same ability as CCL21 in recruiting CCR7-positive cells. Additionally, the CCL21 fusion protein with or without Trx tag showed similar functions. Therefore, the study implies the feasibility of directing a modular genetic method for the development of protein-based drugs.
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Affiliation(s)
- Sitian Li
- Medical 3D Printing Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China; Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450003, PR China
| | - Yongtao Wang
- School of Medicine, Shanghai University, Shanghai 200444, China
| | - Huaiqing Jiang
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450003, PR China
| | - Yueyue Bai
- Medical Research Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China
| | - Tao Chen
- Department of Orthopedic Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China
| | - Min Chen
- Medical 3D Printing Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China
| | - Mengze Ma
- Medical 3D Printing Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China
| | - Shenyu Yang
- Medical 3D Printing Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China
| | - Yan Wu
- Medical 3D Printing Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China
| | - Chaochen Shi
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450003, PR China
| | - Fazhan Wang
- Medical Research Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China.
| | - Yazhou Chen
- Medical 3D Printing Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450052, PR China; Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450003, PR China.
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Genetic design of co-expressing a novel aconitase with cis-aconitate decarboxylase and chaperone GroELS for high-level itaconic acid production. Process Biochem 2023. [DOI: 10.1016/j.procbio.2023.03.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
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9
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Chen PY, Yi YC, Wang HC, Ng IS. Heterologous Expression of Toxic White Spot Syndrome Virus (WSSV) Protein in Eengineered Escherichia coli Strains. Appl Biochem Biotechnol 2023:10.1007/s12010-023-04369-1. [PMID: 36701096 DOI: 10.1007/s12010-023-04369-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2023] [Indexed: 01/27/2023]
Abstract
Aquacultural shrimps suffer economic lost due to the white spot syndrome virus (WSSV) that is the most notorious virus for its fatality and contagion, leading to a 100% death rate on infected shrimps within 7 days. However, the infection of mechanism remains a mystery and crucial problem. To elucidate the pathogenesis of WSSV, a high abundance of protein is required to identify and characterize its functions. Therefore, the optimal WSSV355 overexpression was explored in engineered Escherichia coli strains, in particular C43(DE3) as a toxic tolerance strain remedied 40% of cell growth from BL21(DE3). Meanwhile, a trace amount of WSSV355 was observed in both strains. To optimize the codon of WSSV355 using codon adaption index (CAI), an overexpression was observed with 1.32 mg/mL in C43(DE3), while the biomass was decreased by 35%. Subsequently, the co-expression with pRARE boosted the target protein up to 1.93 mg/mL. Finally, by scaling up production of WSSV355 in the fermenter with sufficient oxygen supplied, the biomass and total and soluble protein were enhanced 67.6%, 44.9%, and 7.8% compared with that in flask condition. Herein, the current approach provides efficacious solutions to produce toxic proteins via codon usage, strain selection, and processing optimization by alleviating the burden and boosting protein production in E. coli.
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Affiliation(s)
- Po-Yen Chen
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Ying-Chen Yi
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Han-Ching Wang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, 70101, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, 70101, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan.
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Wang X, Feng X, Xue R, Xu H, Wang R, Zhang L, Li S. Promoting soluble expression of hybrid mussel foot proteins by SUMO-TrxA tags for production of mussel glue. Int J Biol Macromol 2023; 225:840-847. [PMID: 36402391 DOI: 10.1016/j.ijbiomac.2022.11.147] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/07/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022]
Abstract
Mussel foot proteins (Mfps) display application potential with strong adhesion, enabling mussels to adhere firmly to various surfaces. Mytilus galloprovincialis foot protein 3B (Mgfp-3B) exhibits this characteristic remarkably. However, it remains a challenge for further research due to the low soluble expression of heterologous production. In this study, a small ubiquitin-related modifier (SUMO) and thioredoxin A (TrxA), which catalyzed the proper folding of disulfide bridges, were selected to increase the soluble expression of mfps. An additional ribosome binding site was introduced between the molecular chaperones and Mgfp-3B (fp-3) to form a bicistronic translation-coupled expression vector for co-expression. The results revealed that the combination of SUMO-TrxA increased the soluble expression of fp-3 by 18.07 %. Furthermore, the SUMO-TrxA also boosted the soluble expression of hybrid mfps Mgfp-3B-Mfp-1 (fp-3-1) by 11.29 %, Mgfp-3B-Mgfp-3B (fp-3-3) by 19.91 %, and Mgfp-3B-Mgfp-5 (fp-3-5) by 14.03 %. Ultimately, by high cell density cultivation in a 5 L bioreactor, the yields of fp-3, fp-3-3, and fp-3-5 co-expressed with SUMO-TrxA reached 217.75 mg/L, 127.2 mg/L, and 97.28 mg/L, respectively. Consequently, soluble production of mfps holds great potential for the sustainable supply of protein adhesive materials.
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Affiliation(s)
- Xinyi Wang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Xinxin Feng
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Rui Xue
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Hong Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Rui Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Lujia Zhang
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Sha Li
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
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Sri Wahyu Effendi S, Lin JY, Ng IS. Simultaneous carbon dioxide sequestration and utilization for cadaverine production using dual promoters in engineered Escherichia coli strains. BIORESOURCE TECHNOLOGY 2022; 363:127980. [PMID: 36137445 DOI: 10.1016/j.biortech.2022.127980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
Human carbonic anhydrase II (hCAII) is a rapid-acting zinc-metalloenzyme that catalyzes CO2 hydration reversibly, with encouraging applications in carbon capture, sequestration, and utilization (CCSU). However, biocatalyst durability is a major challenge. Herein, hCAII is emphasized in 4 different Escherichia coli strains and designated under dual promoters from sigma factor 70 (σ70) and heat shock protein (HSP70A) to suppress the usage of inducer and stimulate activity in heat environments. As a result, hCAII under high-efficient dual promoters regulation retained high residual activity in CO2 biomineralization of 68.8 % after 4 cycles at 40 °C. Moreover, co-expression of CAC9 with lysine decarboxylase (CadA) simultaneously sequestered CO2 release up to 95.7 % and increased cadaverine titer from 18.0 to 36.7 g/L by using E. coli MG1655. The remnant biomass from cadaverine synthesis sustained converting CO2 to 57.9 mg-CaCO3. Thus, the dual promoters design demonstrated the promising potential for CCSU through simultaneous CO2 utilization and cadaverine synthesis.
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Affiliation(s)
| | - Jia-Yi Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
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Ting WW, Yu JY, Lin YC, Ng IS. Enhanced recombinant carbonic anhydrase in T7RNAP-equipped Escherichia coli W3110 for carbon capture storage and utilization (CCSU). BIORESOURCE TECHNOLOGY 2022; 363:128010. [PMID: 36167176 DOI: 10.1016/j.biortech.2022.128010] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
Sulfurihydrogenibium yellowstonense carbonic anhydrase (SyCA) is a well-known thermophilic CA for carbon mineralization. To broaden the applications of SyCA, the activity of SyCA was improved through stepwise engineering and in different cultural conditions, as well as extended to co-expression with other enzymes. The engineered W3110 strains with 4 different T7 RNA polymerase levels were employed for SyCA production. As a result, the best strain WT7L cultured in modified M9 medium with temperature shifted from 37 to 30 °C after induction increased SyCA activity to 9122 U/mL. The SyCA whole-cell biocatalyst was successfully applied for carbon capture and storage (CCS) of CaCO3. Furthermore, SyCA was applied for low-carbon footprint synthesis of 5-aminolevulinic acid (5-ALA) and cadaverine (DAP) by coupling with ALA synthetase (ALAS) and lysine decarboxylase (CadA), suppressing CO2 release to -6.1 g-CO2/g-ALA and -2.53 g-CO2/g-DAP, respectively. Harnessing a highly active SyCA offers a complete strategy for CCSU in a green process.
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Affiliation(s)
- Wan-Wen Ting
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Jie-Yao Yu
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Yu-Chieh Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
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Effendi SSW, Ng IS. Reprogramming T7RNA Polymerase in Escherichia coli Nissle 1917 under Specific Lac Operon for Efficient p-Coumaric Acid Production. ACS Synth Biol 2022; 11:3471-3481. [PMID: 36087056 DOI: 10.1021/acssynbio.2c00363] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Lac operon is the standard regulator used to control the orthogonality of T7RNA polymerase (T7RNAP) and T7 promoter inEscherichia coli BL21(DE3) strain for protein expression. However,E. coliNissle 1917 (EcN), the unique probiotic strain, has seldom been precisely adapted to the T7 system. Herein, we applied bioinformatics analysis on Lac operon from different strains, and it was observed that a weak promoter for LacI repressor existed in EcN. Furthermore, X-gal assay revealed a strong expression of lacZ in EcN. We demonstrated that Lac operon significantly affected the protein expression in the two T7-derived EcN, in which T7RNAP was integrated at lambda (ET7L) and HK022 (ET7H), respectively. Different combinations of replication origin, chaperonin GroELS, inducer, and medium were explored to fine-tune the best strain with tyrosine ammonia-lyase (TAL) for p-coumaric acid (pCA) production, which is one of the essential bioactive compounds for human health. Finally, the highest pCA conversion of 78.8% was achieved using RRtL (plasmid form) under the optimum condition, and a 51.5% conversion was obtained with L::Rt strain which has integrated T7-RtTAL at HK022 of ET7L in the simulated gut environment. The appropriate reprogramming of T7RNAP expedites EcN as an effective and promising cell factory for live bacterial therapeutics in the future.
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Affiliation(s)
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
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14
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Hsiang CC, Diankristanti PA, Tan SI, Ke YC, Chen YC, Effendi SSW, Ng IS. Tailoring key enzymes for renewable and high-level itaconic acid production using genetic Escherichia coli via whole-cell bioconversion. Enzyme Microb Technol 2022; 160:110087. [DOI: 10.1016/j.enzmictec.2022.110087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 05/14/2022] [Accepted: 06/16/2022] [Indexed: 11/29/2022]
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15
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Lin JY, Sri Wahyu Effendi S, Ng IS. Enhanced carbon capture and utilization (CCU) using heterologous carbonic anhydrase in Chlamydomonas reinhardtii for lutein and lipid production. BIORESOURCE TECHNOLOGY 2022; 351:127009. [PMID: 35304253 DOI: 10.1016/j.biortech.2022.127009] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/11/2022] [Accepted: 03/12/2022] [Indexed: 06/14/2023]
Abstract
Chlamydomonas reinhardtii is a model microalga that has a higher growth rate and produces high levels of lutein and lipids, but biomass production is limited. Carbonic anhydrase (CA) converts atmospheric CO2 to bicarbonate which is crucial for carbon-concentrating mechanism (CCM) in microalgae and boosts cell density. Therefore, C. reinhardtii harboring the heterologous CA from Mesorhizobium loti (MlCA) and Sulfurihydrogenibium yellowstonense (SyCA) were explored to increase CO2 capture and utilization (CCU) through different culture devices. Genetically modified C. reinhardtii was able to grow from mixotrophic to autotrophic conditions. Subsequently, biomass, lutein, and lipid were maximized to OD680 of 4.56, 21.32 mg/L and 672 mg/L using photo-bioreactor (PBR) with 5% CO2. Moreover, CO2 assimilation rate was 2.748 g-CO2/g-DCW and 2.792 g-CO2/g-DCW under mixotrophic and autotrophic conditions, respectively. The biomass accumulation correlated with CA activity. In addition, the transcript levels of major genes in metabolic pathways of lutein and lipid were dramatically increased.
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Affiliation(s)
- Jia-Yi Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | | | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
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16
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Zhu Y, Liu Y, Ai M, Jia X. Surface display of carbonic anhydrase on Escherichia coli for CO 2 capture and mineralization. Synth Syst Biotechnol 2022; 7:460-473. [PMID: 34938905 PMCID: PMC8654698 DOI: 10.1016/j.synbio.2021.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 11/25/2021] [Accepted: 11/28/2021] [Indexed: 11/25/2022] Open
Abstract
Mineralization catalyzed by carbonic anhydrase (CA) is one of the most promising technologies for capturing CO2. In this work, Escherichia coli BL21(DE3) was used as the host, and the N-terminus of ice nucleation protein (INPN) was used as the carrier protein. Different fusion patterns and vectors were used to construct CA surface display systems for α-carbonic anhydrase (HPCA) from Helicobacter pylori 26695 and α-carbonic anhydrase (SazCA) from Sulfurihydrogenibium azorense. The surface display system in which HPCA was fused with INPN via a flexible linker and intermediate repeat sequences showed higher whole-cell enzyme activity, while the enzyme activity of the SazCA expression system was significantly higher than that of the HPCA expression system. The pET22b vector with the signal peptide PelB was more suitable for the cell surface display of SazCA. Cell fractionation and western-blot analysis indicated that SazCA and INPN were successfully anchored on the cell's outer membrane as a fusion protein. The enzyme activity of the surface display strain E-22b-IRLS (11.43 U·mL-1OD600 -1) was significantly higher than that of the intracellular expression strain E-22b-S (8.355 U·mL-1OD600 -1) under optimized induction conditions. Compared with free SazCA, E-22b-IRLS had higher thermal and pH stability. The long-term stability of SazCA was also significantly improved by surface display. When the engineered strain and free enzyme were used for CO2 mineralization, the amount of CaCO3 deposition catalyzed by the strain E-22b-IRLS on the surface (241 mg) was similar to that of the free SazCA and was significantly higher than the intracellular expression strain E-22b-S (173 mg). These results demonstrate that the SazCA surface display strain can serve as a whole-cell biocatalyst for CO2 capture and mineralization.
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Affiliation(s)
- Yinzhuang Zhu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China
| | - Yaru Liu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China
| | - Mingmei Ai
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China
| | - Xiaoqiang Jia
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, PR China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, PR China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, PR China
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Yu TH, Tan SI, Yi YC, Xue C, Ting WW, Chang JJ, Ng IS. New insight into the codon usage and medium optimization toward stable and high-level 5-aminolevulinic acid production in Escherichia coli. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2021.108259] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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18
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Xue C, Ng IS. Sustainable production of 4-aminobutyric acid (GABA) and cultivation of Chlorella sorokiniana and Chlorella vulgaris as circular economy. BIORESOURCE TECHNOLOGY 2022; 343:126089. [PMID: 34624471 DOI: 10.1016/j.biortech.2021.126089] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/29/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
The 4-aminobutyric acid (GABA) is important to produce bio-nylon 4 in biorefineries. First, a glutamate decarboxylase (GAD) was propagated in three different Escherichia coli strains to achieve 100% conversion from 1 M monosodium glutamate after optimization of the process. To make the process greener and more efficient, in situ CO2 adaptation and citrate feeding strategies to maintain the optimal pH value and 498 g/L of GABA was obtained. However, the process releases the equivalent amount of CO2. Therefore, CO2 generated from GABA production was completely sequestered in sodium hydroxide to form bicarbonate and applied in a coupling culture of Chlorella sorokiniana (CS) or Chlorella vulgaris (CV) to increase the biomass when combined with sodium bicarbonate and carbonic anhydrase. Further improvement of 1.65-fold biomass and 1.43-fold lipid content were occurred when supplying GABA to the culture. This integrative process provided the highest GABA production rate without CO2 release, forming an eco-friendly and carbon-neutral technology.
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Affiliation(s)
- Chengfeng Xue
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
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19
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Precise measurement of decarboxylase and applied cascade enzyme for simultaneous cadaverine production with carbon dioxide recovery. J Taiwan Inst Chem Eng 2021. [DOI: 10.1016/j.jtice.2021.104188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Xue C, Yi YC, Ng IS. Migration of glutamate decarboxylase by cold treatment on whole-cell biocatalyst triggered activity for 4-aminobutyric acid production in engineering Escherichia coli. Int J Biol Macromol 2021; 190:113-119. [PMID: 34480902 DOI: 10.1016/j.ijbiomac.2021.08.166] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/10/2021] [Accepted: 08/20/2021] [Indexed: 02/05/2023]
Abstract
Glutamate decarboxylase B (GadB) from Escherichia coli, an intrinsic pyridoxal 5'-phosphate (PLP)-dependent enzyme has been employed for 4-aminobutyric acid (GABA) biosynthesis, which involves the glutamate import and GABA export via a transporter located in the inner membrane as rate determined step of whole-cell (WC) biotransformation. Herein, GadB was cloned and overexpressed in E. coli under a constitutive promoter in a high copy number plasmid, and 46.9 g/L GABA was produced. It was observed that GadB migrated to the periplasm when the WC were subjected to -20 °C cold treatment for 24 h prior to the biotransformation. Kinetic studies indicated that the enzymatic turnover rate of WC increased 2-fold after cold treatment, which was correlated with the migration rate of GadB, and up to 88.6% of GadB. The export or possible migration of GadB mitigated the rate-limiting step of WC biotransformation, and a 100% conversion of substrate to GABA was obtained. Finally, we launched a promising strategy for GABA production of 850 g/L from cost-effective monosodium glutamate (MSG) by using WC biocatalysts with 10-times recycling.
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Affiliation(s)
- Chengfeng Xue
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Ying-Chen Yi
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.
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21
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Effendi SSW, Xue C, Tan SI, Ng IS. Whole-cell biocatalyst of recombinant tyrosine ammonia lyase with fusion protein and integrative chaperone in Escherichia coli for high-level p-Coumaric acid production. J Taiwan Inst Chem Eng 2021. [DOI: 10.1016/j.jtice.2021.08.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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22
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Mital S, Christie G, Dikicioglu D. Recombinant expression of insoluble enzymes in Escherichia coli: a systematic review of experimental design and its manufacturing implications. Microb Cell Fact 2021; 20:208. [PMID: 34717620 PMCID: PMC8557517 DOI: 10.1186/s12934-021-01698-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/22/2021] [Indexed: 02/06/2023] Open
Abstract
Recombinant enzyme expression in Escherichia coli is one of the most popular methods to produce bulk concentrations of protein product. However, this method is often limited by the inadvertent formation of inclusion bodies. Our analysis systematically reviews literature from 2010 to 2021 and details the methods and strategies researchers have utilized for expression of difficult to express (DtE), industrially relevant recombinant enzymes in E. coli expression strains. Our review identifies an absence of a coherent strategy with disparate practices being used to promote solubility. We discuss the potential to approach recombinant expression systematically, with the aid of modern bioinformatics, modelling, and ‘omics’ based systems-level analysis techniques to provide a structured, holistic approach. Our analysis also identifies potential gaps in the methods used to report metadata in publications and the impact on the reproducibility and growth of the research in this field.
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Affiliation(s)
- Suraj Mital
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK
| | - Graham Christie
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK
| | - Duygu Dikicioglu
- Department of Biochemical Engineering, University College London, London, WC1E 6BT, UK.
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Whole-cell biocatalyst for cadaverine production using stable, constitutive and high expression of lysine decarboxylase in recombinant Escherichia coli W3110. Enzyme Microb Technol 2021; 148:109811. [PMID: 34116745 DOI: 10.1016/j.enzmictec.2021.109811] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/22/2021] [Accepted: 04/28/2021] [Indexed: 01/09/2023]
Abstract
Microbial production of industrial chemicals is a sustainable approach to reduce the dependence on petroleum-based chemicals such as acids, alcohols, and amines, in which the cadaverine is a natural diamide and serves as one of the key monomers for biopolymer production. In this study, the constitutive promoter J23100 driven lysine decarboxylase (CadA) for cadaverine production was established and compared in different Escherichia coli strains. The best chassis designed as JW, expressed the highest amount of CadA by using J23100 promoter, showing stable and high copy numbers (i.e., PCN > 100) when culture in the antibiotic-free medium. JW attained a CadA activity of 167 g-DAP/g-DCW-h and had the maximum biocatalyst of 45.6 g-DCW/L in fed-batch fermentation. In addition, JW was able to convert 2.5 M L-lysine to 221 g/L cadaverine, with 86 % yield and 55.3 g/L-h productivity. The whole-cell biocatalyst could be reused over four times at an average of 97 % conversion when supplied half of fresh cells in the reaction. This work developed a stable, constitutive expression, long-term preservation, high-level expression of CadA for DAP production, and paved an alternative opportunity of bio-nylon for industry in the future.
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Shih IT, Yi YC, Ng IS. Plasmid-Free System and Modular Design for Efficient 5-Aminolevulinic Acid Production by Engineered Escherichia coli. Appl Biochem Biotechnol 2021; 193:2858-2871. [PMID: 33860878 DOI: 10.1007/s12010-021-03571-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/08/2021] [Indexed: 11/30/2022]
Abstract
5-Aminolevulinic acid (ALA) is an essential intermediate for many organisms and has been considered for the applications of medical especially in photodynamic therapy of cancer recently. However, ALA production via chemical approach is complicated; hence, microbial manufacturing has received more attentions. In this study, a modular design to simultaneously express ALA synthase from Rhodobacter sphaeroides (RshemA), a non-specific ALA exporter (RhtA), and chaperones was first developed and discussed. The ALA production was significantly increased by coexpressing RhtA and RshemA. Besides, ALA was enhanced by the cofactor pyridoxal phosphate (PLP) which was supplied by expressing genes of pdxK and pdxY or direct addition. However, inclusion bodies of RshemA served as an obstacle; thus, chaperones DnaK and GroELS were introduced to reform the conformation of proteins and successfully improved ALA production. Finally, a plasmid-free strain RrGI, as the robust chassis, was established and a 6.23-fold enhancement on ALA biosynthesis and led to 7.47 g/L titer and 0.588 g/L/h productivity under the optimal cultural condition.
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Affiliation(s)
- I-Tai Shih
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Ying-Chen Yi
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan.
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Yi YC, Ng IS. Redirection of metabolic flux in Shewanella oneidensis MR-1 by CRISPRi and modular design for 5-aminolevulinic acid production. BIORESOUR BIOPROCESS 2021; 8:13. [PMID: 38650245 PMCID: PMC10992681 DOI: 10.1186/s40643-021-00366-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 02/01/2021] [Indexed: 11/10/2022] Open
Abstract
Programming non-canonical organisms is more attractive due to the prospect of high-value chemical production. Among all, Shewanella oneidensis MR-1 possesses outstanding heme synthesis ability and is well-known for electron transfer, thus has high potential in microbial fuel cell and bioremediation. However, heme, as the final product of C4 and C5 pathways, is regulated by heme cluster for the high-value 5-aminolevulinic acid (ALA) for cancer photodynamic therapy, which has never been explored in MR-1. Herein, the heme metabolism in MR-1 was firstly optimized for ALA production. We applied CRISPR interference (CRISPRi) targeted on the genes to fine-tune carbon flux in TCA cycle and redirected the carbon out-flux from heme, leading to a significant change in the amino acid profiles, while downregulation of the essential hemB showed a 2-fold increasing ALA production via the C5 pathway. In contrast, the modular design including of glucokinase, GroELS chaperone, and ALA synthase from Rhodobacter capsulatus enhanced ALA production markedly in the C4 pathway. By integrating gene cluster under dual T7 promoters, we obtained a new strain M::TRG, which significantly improved ALA production by 145-fold. We rewired the metabolic flux of MR-1 through this modular design and successfully produced the high-value ALA compound at the first time.
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Affiliation(s)
- Ying-Chen Yi
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan.
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